#include <iostream>
#include <string>

inline auto get_discount_string(int price, int n_percent) {
    auto s = std::to_string(price * n_percent * 10);
    s.insert(s.size() - 2, 1, '.');
    if (s.front() == '.') { s.insert(0, 1, '0'); }
    return s;
}

int main() {
    int price;
    int n_percent;

    std::cin >> price >> n_percent;
    
    std::cout << get_discount_string(price, n_percent);
}
